1. ATTRA // POSTHARVEST HANDLING OF FRUITS & VEGETABLES Page 1111
By Janet Bachmann and Richard Earles
NCAT Agriculture Specialists
August 2000
IntroductionIntroductionIntroductionIntroduction
You have spent
months working in
the fields, and now
have a bountiful
harvest of beautiful
fruits and
vegetables. You
want to ensure that
your customers will
also enjoy this
healthy harvest.
How can you best
maintain the quality
and safety of your produce as it travels from the
field to the table? How can produce be stored so
that it does not need to be sold immediately?
High-quality, disease-free produce with a good
shelf life is a result of sound production practices,
proper handling during harvest, and appropriate
postharvest handling and storage.
Production PracticesProduction PracticesProduction PracticesProduction Practices
Production practices have
a tremendous effect on the
quality of fruits and
vegetables at harvest and
on postharvest quality
and shelf life. To start
with, it is well known that
some cultivars ship better
and have a longer shelf life than others. In
addition, environmental factors such as soil type,
temperature, frost, and
rainy weather at
harvest can have an
adverse effect on
storage life and quality.
For example, carrots
grown on muck soils
do not hold up as well
in storage as carrots
grown on lighter,
upland soils. Lettuce
harvested during a
period of rain does not
ship well and product
losses are increased (1).
Management practices can also affect
postharvest quality. Produce that has been
stressed by too much or too little water, high
rates of nitrogen, or mechanical injury (scrapes,
bruises, abrasions) is particularly susceptible to
postharvest diseases. Mold and decay on winter
squash, caused by the fungus Rhizoctonia, result
from the fruits lying on the ground, and can be
alleviated by using mulch.
Broccoli heads are
susceptible to postharvest
rot caused by the bacteria
Erwinia if nitrogen is applied
as foliar feed—a grower
should feed the soil, not the
leaves. Beets and radishes
are susceptible to soil-borne
diseases when the soil
800-346-9140
AppropriateTechnologyTransferforRuralAreas
POSTHARVEST HANDLING OF
FRUITS AND VEGETABLES
Abstract: Appropriate production practices, careful harvesting, and proper packaging, storage, and transport all
contribute to good produce quality. This publication covers postharvest practices suitable for small-scale
operations, and points out the importance of production and harvesting techniques for improving quality and
storability. Various methods for cooling fresh produce are discussed, and resources are listed for further
information, equipment, and supplies.
ATTRA is the national sustainable agriculture information center funded by the USDA’s Rural Business -- Cooperative Service.
Contents:
Production Practices....................................... 1
Harvest Handling........................................... 2
Postharvest & Storage .................................. 2
References .................................................... 8
Enclosures ..................................................... 9
Resources...................................................... 9
Appendix I: Storage Conditions ......................... 13
Appendix II: The Portacooler............................. 15
HORTICULTURE TECHNICAL NOTE

2. ATTRA // POSTHARVEST HANDLING OF FRUITS & VEGETABLES Page 2222
temperature reaches 80º F; symptoms are black
spots on these root crops (2).
Food safety also begins in the field, and should
be of special concern, since a number of
outbreaks of foodborne illnesses have been traced
to contamination of produce in the field.
Common-sense prevention measures include a
number of don’ts (3):
• Don’t apply raw dairy or chicken manure or
slurries to a field where a vegetable crop such
as leafy lettuce is growing.
• Don’t apply manure to an area
immediately adjacent to a field nearing
harvest maturity.
• Don’t forget to clean equipment that has been
used to apply manure to one field before
moving it to another field in production.
• Don’t irrigate with water from a farm pond
used by livestock.
• Don’t harvest fruit from the orchard floor for
human consumption as whole fruit or
nonpasteurized juices, especially if manure
has been spread or animals allowed to graze.
• Don’t accumulate harvested product in areas
where birds roost.
A grower should constantly evaluate water used
for irrigation, and compost all animal manures
before applying them to fields. There are many
good sources of information on growing
conditions and production practices that promote
postharvest quality. Consult textbooks,
Extension publications, and trade journals, and
become involved with grower organizations to
find out more.
Harvest HandlingHarvest HandlingHarvest HandlingHarvest Handling
Quality cannot be improved after harvest,
only maintained; therefore it is important to
harvest fruits, vegetables, and flowers at the
proper stage and size and at peak quality.
Immature or overmature produce may not
last as long in storage as that picked at proper
maturity (4). Cooperative Extension Service
publications are an excellent source of
information on harvest maturity indicators
for vegetables and fruits.
Harvest should be completed during the coolest
time of the day, which is usually in the early
morning, and produce should be kept shaded in
the field. Handle produce gently. Crops
destined for storage should be as free as possible
from skin breaks, bruises, spots, rots, decay, and
other deterioration. Bruises and other
mechanical damage not only affect appearance,
but provide entrance to decay organisms as well.
Postharvest rots are more prevalent in fruits and
vegetables that are bruised or otherwise damaged.
Mechanical damage also increases moisture loss.
The rate of moisture loss may be increased by as
much as 400% by a single bad bruise on an apple,
and skinned potatoes may lose three to four times
as much weight as non-skinned potatoes. Damage
can be prevented by training harvest labor to
handle the crop gently; harvesting at proper
maturity; harvesting dry whenever possible;
handling each fruit or vegetable no more than
necessary (field pack if possible); installing
padding inside bulk bins; and avoiding over or
under-packing of containers (4).
Postharvest and Storage ConsiderationsPostharvest and Storage ConsiderationsPostharvest and Storage ConsiderationsPostharvest and Storage Considerations
Packaging
Packaging should be designed to prevent physical
damage to produce, and be easy to handle. The
American Vegetable Grower magazine’s annual
product guide is a good source of information
about suppliers (see Resources).
Temperature
Temperature is the single most important factor
in maintaining quality after harvest. Refrigerated
storage retards the following elements of
deterioration in perishable crops:
• aging due to ripening, softening, and textural
and color changes;
• undesirable metabolic changes and
respiratory heat production;
• moisture loss and the wilting that results;
• spoilage due to invasion by bacteria, fungi,
and yeasts;
• undesirable growth, such as sprouting of
potatoes (5).

3. ATTRA // POSTHARVEST HANDLING OF FRUITS & VEGETABLES Page 3333
One of the most important functions of
refrigeration is to control the crop’s respiration
rate. Respiration generates heat as sugars, fats,
and proteins in the cells of the crop are
oxidized. The loss of these stored food reserves
through respiration means decreased food
value, loss of flavor, loss of salable weight, and
more rapid deterioration. The respiration rate
of a product strongly determines its transit and
postharvest life. The higher the storage
temperature, the higher the respiration rate
will be (4).
For refrigeration to be effective in postponing
deterioration, it is important that the temperature
in cold storage rooms be kept as constant as
possible. Appendix I charts the optimum
temperature ranges for various crops. Exposure
to alternating cold and warm temperatures may
result in moisture accumulation on the surface of
produce (sweating), which may hasten decay.
Storage rooms should be well insulated and
adequately refrigerated, and should allow for air
circulation to prevent temperature variation. Be
sure that thermometers, thermostats, and manual
temperature controls are of high quality, and
check them periodically for accuracy (5).
On-farm cooling facilities are a valuable asset for
any produce operation. A grower who can cool
and store produce has greater market flexibility
because the need to market immediately after
harvest is eliminated. The challenge, especially
for small-scale producers, is the set-up cost.
Innovative farmers and researchers have created
a number of designs for low-cost structures.
Some of these ideas are detailed in Appendix II
and in the enclosures attached to this document.
Additional designs are available in publications
listed in the Resources section.
Pre-cooling
Pre-cooling is the first step in good temperature
management. The field heat of a freshly harvested
crop—heat the product holds from the sun and
ambient temperature—is usually high, and
should be removed as quickly as possible before
shipping, processing, or storage. Refrigerated
trucks are not designed to cool fresh commodities
but only maintain the temperature of pre-cooled
produce. Likewise, most refrigerated storage
rooms have neither the refrigeration capacity nor
the air movement needed for rapid cooling.
Therefore, pre-cooling is generally a separate
operation requiring special equipment and/or
rooms (4, 5).
Rapid pre-cooling to the product’s lowest safe
temperature is most critical for crops with
inherently high respiration rates. These include
artichokes, brussels sprouts, cut flowers, green
onions, snap beans, asparagus, broccoli,
mushrooms, peas, and sweet corn. Crops with
low respiration rates include nuts, apples, grapes,
garlic, onions, potatoes (mature), and sweet
potatoes (4).
Appropriate pre-cooling methods as well as
appropriate storage temperature and humidity
for a number of fruits and vegetables are shown
in Appendix I. The following methods are the
most commonly used:
• Room cooling: Produce is placed in an
insulated room equipped with refrigeration
units. This method can be used with most
commodities, but is slow compared with
other options. A room used only to store
previously cooled produce requires a
relatively small refrigeration unit. However,
if it is used to cool produce, a larger unit is
needed. Containers should be stacked so that
cold air can move around them, and
constructed so that it can move through them.
Used refrigerated truck bodies make excellent
small cooling rooms (4).
• Forced-air cooling: Fans are used in
conjunction with a cooling room to pull cool air
through packages of produce. Although the
cooling rate depends on the air temperature
and the rate of air flow, this method is usually
75–90% faster than room cooling. Fans should
be equipped with a thermostat that
automatically shuts them off as soon as the
desired product temperature is reached.
To avoid over-cooling and dehydration of produce,To avoid over-cooling and dehydration of produce,To avoid over-cooling and dehydration of produce,To avoid over-cooling and dehydration of produce,
do not operate forced-air fans after the prdo not operate forced-air fans after the prdo not operate forced-air fans after the prdo not operate forced-air fans after the prooooduceduceduceduce
has been cooled to its optimum tehas been cooled to its optimum tehas been cooled to its optimum tehas been cooled to its optimum temmmmperature (4).perature (4).perature (4).perature (4).

4. ATTRA // POSTHARVEST HANDLING OF FRUITS & VEGETABLES Page 4444
• Hydro-cooling: Dumping produce into cold
water, or running cold water over produce,
is an efficient way to remove heat, and can
serve as a means of cleaning at the same
time. In addition, hydro-cooling reduces
water loss and wilting. Use of a disinfectant
in the water is recommended to reduce the
spread of diseases. Hydro-cooling is not
appropriate for berries, potatoes to be
stored, sweet potatoes, bulb onions,
garlic, or other commodities that cannot
tolerate wetting.
Water removes heat about five times faster
than air, but is less energy-efficient. Well
water is a good option, as it usually comes
out of the ground with temperatures in the
50–60º F range. Mechanical refrigeration is
the most efficient method for cooling water.
A thermal storage immersion hydro-cooler
system can be fabricated economically to suit
various volume requirements. Used
stainless-steel bulk farm milk coolers may be
an option. If hydro-cooling water is
recirculated, it should be chlorinated to
minimize disease problems (4).
A study compared sweet corn quality after
hydro-cooling with ice water, well water
cooling, and refrigerated air cooling, and
subsequent refrigerated storage. Hydro-
cooling with ice water lowered the
temperature of the ears most quickly. Well
water cooling followed by refrigerated
storage appeared to offer no advantage over
refrigerated storage immediately after
harvest (6).
• Top or liquid icing: Icing is particularly
effective on dense products and palletized
packages that are difficult to cool with forced
air. In top icing, crushed ice is added to the
container over the top of the produce by hand
or machine. For liquid icing, a slurry of water
and ice is injected into produce packages
through vents or handholds without
removing the packages from pallets and
opening their tops. Icing methods work well
with high-respiration commodities such as
sweet corn and broccoli. One pound of ice
will cool about three pounds of produce from
85º F to 40º F (7, 8).
• Vacuum cooling: Produce is enclosed in a
chamber in which a vacuum is created.
As the vacuum pressure increases, water
within the plant evaporates and removes
heat from the tissues. This system works
best for leafy crops, such as lettuce, which
have a high surface-to-volume ratio. To
reduce water loss, water is sometimes
sprayed on the produce prior to placing it
in the chamber. This process is called
hydrovac cooling. The primary drawback
to this method is the cost of the vacuum
chamber system (9).
These products can be iced:
Artichokes
Asparagus
Beets
Broccoli
Cantaloupes
Carrots
Cauliflower
Endive
Green onions
Leafy greens
Radishes
Spinach
Sweet corn
Watermelon

5. ATTRA // POSTHARVEST HANDLING OF FRUITS & VEGETABLES Page 5555
These items are damaged by direct contact with ice:
Strawberries
Blueberries
Raspberries
Tomatoes
Squash
Green beans
Cucumbers
Garlic
Okra
Bulb onions
Romaine lettuce
Herbs
Chilling injury
Many vegetables and fruits store best at
temperatures just above freezing, while others
are injured by low temperatures and will store
best at 45 to 55 degrees F. Both time and
temperature are involved in chilling injury.
Damage may occur in a short time if
temperatures are considerably below the danger
threshold, but some crops can withstand
temperatures a few degrees into the danger zone
for a longer time. The effects of chilling injury are
cumulative in some crops. Low temperatures in
transit, or even in the field shortly before harvest,
add to the total effects of chilling that might occur
in storage (7).
Crops such as basil, cucumbers, eggplants,
pumpkins, summer squash, okra, and sweet
potatoes are highly sensitive to chilling injury.
Moderately sensitive crops are snap beans,
muskmelons, peppers, winter squash, tomatoes,
and watermelons (8). These crops may look
sound when removed from low temperature
storage, but after a few days of warmer
temperatures, chilling symptoms become
evident: pitting or other skin blemishes, internal
discoloration, or failure to ripen. Tomatoes,
squash, and peppers that have been over-chilled
may be particularly susceptible to decay such as
Alternaria rot (7).
Preventing moisture loss
While temperature is the primary concern in the
storage of fruits and vegetables, relative humidity
is also important. The relative humidity of the
storage unit directly influences water loss in
produce. Water loss can severely degrade
quality—for instance, wilted greens may require
excessive trimming, and grapes may shatter loose
from clusters if their stems dry out. Water loss
means salable weight loss and reduced profit (4).
Most fruit and vegetable crops retain better
quality at high relative humidity (80 to 95%), but
at this humidity, disease growth is encouraged.
The cool temperatures in storage rooms help to
reduce disease growth, but sanitation and other
preventative methods are also required.
Maintaining high relative humidity in storage is
complicated by the fact that refrigeration
removes moisture. Humidification devices such
as spinning disc aspirators may be used. Even
buckets of water will increase humidity as the
fans blow air across the water’s surface and
increase evaporation (10). Keeping the floor wet
is helpful, though messy and potentially
hazardous to two-legged creatures; frequent
cleansing with a weak chlorine solution will be
needed to prevent harboring of disease
organisms in water and produce scraps on the
floor. Crops that can tolerate direct contact with
water may be sprinkled to promote high relative
humidity (4).
When it comes to maintaining appropriate
humidity levels, “the biggest thing for small
growers is going to be monitoring equipment,”
says Kansas State University Extension Specialist
Karen Gast. Humidity is measured by an
instrument called a hygrometer. Several
companies offer small, low-priced hygrometers

6. ATTRA // POSTHARVEST HANDLING OF FRUITS & VEGETABLES Page 6666
suitable for small-scale producers (10). See
Resources for more information.
Sanitation
Sanitation is of great concern to produce
handlers, not only to protect produce against
postharvest diseases, but also to protect
consumers from foodborne illnesses. E. coli
0157:H7, Salmonella, Chryptosporidium, Hepatitis,
and Cyclospera are among the disease-causing
organisms that have been transferred via fresh
fruits and vegetables (3, 11). Use of a
disinfectant in wash water can help to prevent
both postharvest diseases and foodborne
illnesses.
Chlorine in the form of a sodium hypochlorite
solution (for example, Clorox™) or as a dry,
powdered calcium hypochlorite can be used in
hydro-cooling or wash water as a disinfectant.
Some pathogens such as Chryptosporidium,
however, are
very resistant to
chlorine, and
even sensitive
ones such as
Salmonella and
E. coli may be
located in
inaccessible
sites on the
plant surface.
For the majority
of vegetables,
chlorine in
wash water
should be
maintained in the range of 75–150 ppm (parts per
million.) The antimicrobial form, hypochlorous
acid, is most available in water with a neutral pH
(6.5 to 7.5).
The effectiveness of chlorine concentrations are
reduced by temperature, light, and interaction
with soil and organic debris. The wash water
should be tested periodically with a monitoring
kit, indicator strips, or a swimming pool-type
indicator kit. Concentrations above 200 ppm
can injure some vegetables (such as leafy greens
and celery) or leave undesirable off-flavors.
Organic growers must use chlorine with
caution, as it is classified as a restricted
material. The California Certified Organic
Farmers regulations permit a maximum of 4
ppm residual chlorine, measured downstream
of the product wash (3). Growers certified by
other agencies should check with their
certifying agent.
Ozonation is another technology that can be used
to sanitize produce. A naturally occurring
molecule, ozone is a powerful disinfectant.
Ozone has long been used to sanitize drinking
water, swimming pools, and industrial
wastewater. Fruit and vegetable growers have
begun using it in dump tanks as well, where it
can be thousands of times more effective than
chlorine. Ozone not only kills whatever
foodborne pathogens might be present, it also
destroys microbes responsible for spoilage. A
basic system consists of an ozone generator, a
monitor to gauge and adjust the levels of ozone
being produced, and a device to dissolve the
ozone gas into the water. Systems cost anywhere
from $10,000 to $100,000, and should be installed
by an ozone sanitation company experienced in
produce industry applications (12).
Hydrogen peroxide can also be used as a
disinfectant. Concentrations of 0.5% or less
are effective for inhibiting development of
postharvest decay caused by a number of fungi.
Hydrogen peroxide has a low toxicity rating and
is generally recognized as having little potential
for environmental damage. The ATTRA
Amounts of hypochlorite to add to clear, clean water for disinfestation.
target ppm ounces/5 gallons cup/50 gallons
Sodium hypochlorite 50 .55 .5
(5.25%) 75 .8 .75
100 1.1 1.0
125 1.4 1.25
150 1.7 1.5
Sodium hypochlorite 50 .12 .1
(12.7%) 75 .17 .15
100 .23 .2
125 .29 .25
150 .35 .3

7. ATTRA // POSTHARVEST HANDLING OF FRUITS & VEGETABLES Page 7777
publication Sources for Organic Fertilizers and
Amendments lists several sources of food-grade
hydrogen peroxide.
Creative growers can customize their produce-
washing system to promote sanitation and
increase efficiency and ease of operation. At
Drumlin Community Farm in Madison,
Wisconsin, the crew “used to wash greens and
small crops by the handfuls in wash tubs and air
dry them on screen tables. Now they line harvest
containers with a mesh produce bag, dunk the
whole bagful at once, and dry two bagfuls at a
time in an old washing machine set to spin
cycle.” At another farm, loose greens are
dumped into a 500-gallon bulk milk tank. The
water in the tank is agitated with bubbling air
from a jacuzzi motor. The washed greens are
scooped out of the tank with a mesh bag-lined
laundry basket, and the bags of greens are then
spun dry in a washing machine. The grower
removed the washer’s agitator to make more
room for the produce (13).
This type of system has several advantages—it
reduces handling (and potential damage) of the
crop; it makes the washing process more time
and labor efficient; and it enhances postharvest
quality by getting the crop cooled down,
washed, dried, and in cold storage much more
quickly. Perhaps most importantly, washing
greens in large batches rather than one-by-one
reduces physical stress on the worker’s back and
arms.
At a cost of $2–8 each, woven polyester or nylon
bags are durable, lightweight, water-permeable,
and fast-drying. Suitable mesh laundry bags may
be found at hardware or discount stores (13). The
Resources section lists two companies that sell
mesh bags by mail order. Spin-drying can be
done with a washing machine, honey extractor,
or commercial salad spinner. A restaurant or
industrial-scale salad spinner is an efficient
machine for both washing and drying greens
(available from restaurant supply stores; prices
range from $650 to $1500).
Some further tips for postharvest handling of
lettuce and other leafy greens: package in
breathable or perforated plastic bags; refrigerate
at 33º F; carry to market in a portable cooler,
either refrigerated or with ice, and keep in the
cooler until ready to display. If displaying
unwrapped heads at a farmers’ market, mist
occasionally with cold water.
Ethylene
Ethylene, a natural hormone produced by some
fruits as they ripen, promotes additional
ripening of produce exposed to it. The old
adage that one bad apple spoils the whole
bushel is true. Damaged or diseased apples
produce high levels of ethylene and stimulate
the other apples to ripen too quickly. As the
fruits ripen, they become more susceptible to
diseases.
Ethylene “producers” should not be stored with
fruits, vegetables, or flowers that are sensitive to
it. The result could be loss of quality, reduced
shelf life, and specific symptoms of injury. Some
examples of ethylene effects include:
• russet spotting of lettuce along the midrib of
the leaves;
• loss of green color in snap beans;
• increased toughness in turnips and asparagus
spears;
• bitterness in carrots and parsnips;
• yellowing and abscission of leaves in broccoli,
cabbage, Chinese cabbage, and cauliflower;
• accelerated softening of cucumbers, acorn
and summer squash;
• softening and development of off-flavor in
watermelons;
• browning and discoloration in eggplant pulp
and seed;
• discoloration and off-flavor in sweet potatoes;
• sprouting of potatoes;
• increased ripening and softening of mature
green tomatoes (8); and
• shattering of raspberries and blackberries (2).
Ethylene producers include apples, apricots,
avocados, ripening bananas, cantaloupes,
honeydew melons, ripe kiwifruit, nectarines,
papayas, passionfruit, peaches, pears,
persimmons, plantains, plums, prunes, quinces,
and tomatoes (14). Produce that is sensitive to
ethylene is indicated in Appendix I.

8. ATTRA // POSTHARVEST HANDLING OF FRUITS & VEGETABLES Page 8888
Mixed loads
When different commodities are stored or
transported together, it is important to combine
only those products that are compatible with
respect to their requirements for temperature,
relative humidity, atmosphere (oxygen and
carbon dioxide), protection from odors, and
protection from ethylene (4).
In regard to cross-transfer of odors, combinations
that should be avoided in storage rooms include:
apples or pears with celery, cabbage, carrots,
potatoes, or onions; celery with onions or carrots;
and citrus with any of the strongly scented
vegetables. Odors from apples and citrus are
readily absorbed by meat, eggs, and dairy
products. Pears and apples acquire an
unpleasant, earthy taste and odor when stored
with potatoes. It is recommended that onions,
nuts, citrus, and potatoes each be stored
separately (4).
Storage crops
What about the crops that will not be transported
and marketed fresh after harvest? Growers can
extend their selling season into the winter
months by growing root crops and other
vegetables and fruits suited for long-term storage.
The challenge is in keeping quality high by
creating and maintaining the correct storage
environment. As Growing for Market editor Lynn
Byczynski notes,
Most storage crops require low temperatures
and high humidity, two factors that don’t
come together easily. Several others require
low humidity and low temperatures. And
then there are a few that fall in between…Root
crops such as beets, carrots, turnips, rutabagas,
and leeks store best at 32º F and 90%
humidity. Potatoes prefer temperatures of 40–
60º F and 90% humidity. Onions and garlic
like it cool—32º—but require less humidity—
about 65–75%. Winter squash prefer
temperatures of 50–60º F, but dry. That’s four
different types of storage for vegetables that
will hold a month or more: cold and humid;
cold and dry; cool and humid; cool and
dry (10).
The two structural options for storage of these
crops are coolers and root cellars. Byczynski
provides an example of a farm using both: “The
Seelys have a bank barn, which has the bottom
floor built into a hillside…They have built both
coolers and a dry storage room into the lower
floor to provide different combinations of
temperature and humidity for the vegetables they
store.” Coolers used for root crop storage will
require water added to the air and regular
monitoring of the humidity level (see discussion
under Preventing moisture loss above.) Some
growers have used concrete basements of houses,
closed off from heat and with ventilation to let in
cold winter air, as root cellars. Another idea is to
bury a big piece of culvert under a hillside (10).
Whatever the method, only “perfect” produce is
suitable for long-term storage, so careful
inspection is critical. Any damaged produce is
going to spoil and induce spoilage in the rest of
the crop. Byczynski advises growers to “either
rub off soil and leave the crops somewhat dirty,
or wash them and let them dry thoroughly before
putting them in storage. With onions, garlic,
winter squash, pumpkins and sweet potatoes, it’s
important that they be cured thoroughly before
storage” (10).
ConclusionConclusionConclusionConclusion
Postharvest handling is the final stage in the
process of producing high quality fresh produce.
Being able to maintain a level of freshness from
the field to the dinner table presents many
challenges. A grower who can meet these
challenges, will be able to expand his or her
marketing opportunities and be better able to
compete in the marketplace. This document is
intended to serve as an introduction to the topic
and a resource pointer; the grower is advised to
seek out more complete information from
Extension and other sources.
References:
1) Herner, Robert C. 1989. Sources of loss cited
during post harvest handling. Great Lakes
Vegetable Growers News. May. p. 16.

9. ATTRA // POSTHARVEST HANDLING OF FRUITS & VEGETABLES Page 9999
2) Andersen, Craig. 1998. Postharvest handling
workshop. Huntsville, AR. February 22.
3) Suslow, Trevor. 1997. Microbial food safety:
an emerging challenge for small-scale growers.
Small Farm News. June–July. p. 7–10.
4) Wilson, L.G., M.D. Boyette, and E.A. Estes.
1995. Postharvest Handling and Cooling of
Fresh Fruits, Vegetables and Flowers for Small
Farms. Leaflets 800–804. North Carolina
Cooperative Extension Service. 17 p.
Accessed on-line at:
http://www.foodsafety.org/nc/nc1055.htm
5) Hardenburg, Robert, et al. 1986. The
Commercial Storage of Fruits, Vegetables, and
Florist and Nursery Stocks. USDA Handbook
No. 66. United States Department of
Agriculture, Agricultural Research
Service. 136 p.
6) Wilhelm, Luther R. et al. 1992. Effect of
cooling treatment on the quality of sweet corn.
Tennessee Farm and Home Science. Winter.
p. 30–35.
7) Anon. 1992. Put it on ice. American
Vegetable Grower. June. p. 17–18.
8) Howell, John C., editor. 1993. Postharvest
handling. Vegetable Notes: Growing and
Marketing Information for Massachusetts
Commercial Growers. p. 1–5
9) Sasseville, David N. 1988. Harvesting and
handling produce: Plan now for high quality.
Missouri Farm. May–June. p. 19–21.
10) Byczynski, Lynn. 1997. Storage crops extend
the season. Growing for Market. September.
p. 1, 4–5.
11) Melnick, Rick. 1998. Safety sets the table.
American Vegetable Grower. February. p. 9–
11, 13, 15.
12) Gooch, Jamie. 1998. Getting into the ‘o’zone.
Fruit Grower. January. p. 10–11.
13) Newenhouse, Astrid. 1998. Line harvest
containers with mesh bags for washing.
Growing for Market. December. p. 8.
14) Aylesworth, Jean. 1992. Deliver quality.
American Vegetable Grower. June. p. 19–20.
Enclosures:
Joyce, Daryl and Michael Reid. 1992. Postharvest
handling of fresh culinary herbs. Herbal
Connection. Vol. 2, No. 5. p. 7–9.
Brun, Charles A. 1994. On-farm refrigeration.
Pacific Northwest Sustainable Agriculture.
June. p. 4–5.
Nagangast, Dan. 1995. Low-cost cooler uses old
air conditioner. Growing for Market.
November. p. 14.
Resources:
Further Information
Commercial Cooling of Fruits, Vegetables, and Flowers.
By James Thompson, et al. 1998. 65 p.
University of California, ANR
Publications # 21567
Detailed descriptions of proper temperature
management for perishables and commercial
cooling methods. Complete discussion of design for
hydro-cooler and forced-air cooler systems, the two
most commonly used cooling methods. 25 graphs
and illustrations, 11 color plates, and 15 tables.
Available for $10 plus $3.50 s/h. Make check
payable to UC Regents and specify pub. #21567.
University of California
ANR Communication Services
6701 San Pablo Avenue
Oakland, CA 94608-1239
(800) 994-8849
http://anrcatalog.ucdavis.edu
UC-Davis Produce Facts website
http://postharvest.ucdavis.edu/Produce/ProduceFac
ts/index.html
Separate postharvest fact sheets for a great variety
of fruit, vegetable, and ornamental crops. Each fact
sheet includes information about maturity and
quality indices, optimum temperature and relative
humidity, rates of respiration and ethylene
production rates, responses to ethylene and
controlled atmospheres, physiological and
pathological disorders: causes and control, and
other relevant information. Periodic updates of
these fact sheets will be published as new
information becomes available. The goal is to
eventually post fact sheets for all major perishable
crops.

10. ATTRA // POSTHARVEST HANDLING OF FRUITS & VEGETABLES Page 10101010
Perishables Handling
Editor: Pam Moyer
Postharvest Technology
Dept. of Pomology
One Shields Ave.
Univ. of California
Davis, CA 95616-8683
(530) 752-6941
Perishables Handling, a quarterly publication
from the UC-Davis Postharvest Outreach
Program, reports research in progress, recent
publications, and brief reviews of various aspects of
postharvest technology of horticultural crops. A
one-year subscription costs $25. Back issues are
available for $8 each. Tables of contents of back
issues may be reviewed on-line at:
http://postharvest.ucdavis.edu/Pubs/
POSTPhn.html
Produce Handling for Direct Marketing
Natural Resource, Agriculture, and Engineering
Service (NRAES)
1992. 26 p. NRAES-51.
For growers selling seasonal produce at farmers’
markets and roadside stands. Describes
postharvest physiology, food safety, produce
handling from harvest to storage, refrigeration,
produce displays, and specific handling
recommendations for over 40 fruits and vegetables.
Includes eleven tables and eight figures.
Refrigeration and Controlled Atmosphere Storage for
Horticultural Crops
1990. 44 p. NRAES-22
General construction procedures for storage
facilities: structural considerations, site selection,
thermal insulation, vapor barriers, and attic
ventilation. Explanations of various refrigeration
systems, with descriptions of equipment and
operating procedures. Controlled atmosphere
storage construction, testing, and operation,
especially in relation to apple storage.
Both of these NRAES publications are available, for
$8 each plus a total of $3.75 s/h, from:
NRAES
Cooperative Extension
152 Riley-Robb Hall
Ithaca, NY 14853-5701
(607) 255-7654
http://www.nraes.org
Postharvest Handling & Cooling of Fresh Fruits,
Vegetables, and Flowers for Small Farms
By L.G. Wilson, M.D. Boyette, and E.A. Estes.
1995. 17 p.
North Carolina Cooperative Extension Service.
Leaflets 800–804.
Five-part series: Quality Maintenance; Cooling;
Handling; Mixed Loads; References. Available on-
line at:
http://www.ces.ncsu.edu/depts/hort/hil/
post-index.html
North Carolina State University also offers the
following fact sheets on postharvest cooling and
handling, at:
www5.bae.ncsu.edu/programs/extension/
publicat/postharv/index.html
Apples AG-413-1
Strawberries AG-413-2
Peppers AG-413-3
Sweet Corn AG-413-4
Cabbage and Leafy Greens AG-413-5
Onions AG-413-6
Blueberries AG-413-7
Greenbeans and Field Peas AG-413-8
Tomatoes AG-413-9
Proper Postharvest Cooling and Handling
Methods AG-414-1
Design of Room Cooling Facilities AG-414-2
Forced-Air Cooling AG-414-3
Hydrocooling AG-414-4
Crushed and Liquid Ice Cooling AG-414-5
Chlorination and Postharvest Disease Control
AG-414-6
Cool and Ship: Low Cost Portable Forced Air
Cool Unit AG-414-7
Packaging Requirements for Fresh Fruits and
Vegetables AG-414-8
For information on ordering print copies of these
publications, contact:
North Carolina State University
Dept. of Communication Services
Box 7603
Raleigh, NC 27695-7603
(919) 515-2861
Kansas State University offers the following publications
on postharvest management of commercial horticultural
crops. All are available on-line at:
http://www.oznet.ksu.edu/library
Containers and Packaging—Fruits and
Vegetables MF979
Fruits and Vegetables—Precooling Produce
MF1002
Harvest Maturity Indicators for Fruits and
Vegetables MF1175

11. ATTRA // POSTHARVEST HANDLING OF FRUITS & VEGETABLES Page 11111111
Storage Conditions—Fruits and Vegetables
MF978
Storage Construction MF1039
Storage Operations MF1033
Storage Options MF1030
For information on ordering print copies, contact:
Production Services
Kansas State University
24 Umberger Hall
Manhattan, KS 66506-3402
(785) 532-5830
e-mail: orderpub@oz.oznet.ksu.edu
The University of Wisconsin has produced a very helpful
set of “Work Efficiency Tip Sheets” for fresh-market
vegetable growers. These materials were developed by the
Healthy Farmers, Healthy Profits Project, with the goal
of sharing labor-efficiency practices that maintain farmers’
health and safety while increasing profits. Topics in the
series include:
A Specialized Harvest Cart for Greens A3704-1
Stooping or kneeling and crawling to
harvest salad greens requires a lot of time
and energy. An alternative is to build a
simple cart that allows you to sit and roll
while you harvest. The cart also holds
your harvest container, so it rolls along
with you. Parts for the cart will cost
about $150.
Mesh Produce Bags: Easy Batch Processing
A3704-2
Elements and benefits of the batch method
for washing greens, as discussed above
under the heading “Sanitation.”
Standard Containers A3704-3
Standard containers for carrying and
moving produce are made of molded
plastic, have sturdy handles, and are
stackable. They’re easier to use and more
efficient than bushel baskets, buckets or
wooden crates.
Narrow Pallet System A3704-4
If you currently carry boxes of produce by
hand, switching to a narrow pallet system
may save you time and money. With a
hand pallet truck you can move up to 16
half-bushel boxes at a time. This system
can cut your time spent moving boxes by
more than 60% and will dramatically
reduce the stress put on your body.
These tipsheets may be ordered from the following
address, or accessed on-line at:
http://www.bse.wisc.edu/hfhp/
Cooperative Extension Publishing
Rm. 170, 630 W. Mifflin St.
Madison, WI 53703
(608) 262-3346
http://www.uwex.edu/ces/pubs/
Sydney Postharvest Lab
http://www.postharvest.com.au
This Australian website offers postharvest handling
and storage information, with extensive links to
other postharvest sites.
Growing for Market
Editor: Lynn Byczynski
P.O. Box 3747
Lawrence, KS 66046
(800) 307-8949
This monthly newsletter is a great resource for
small-scale growers. Lots of good, practical
information from other producers, with frequent
coverage of postharvest topics. Subscriptions cost
$30. for one year, or $55. for two years.
Manufacturers & Suppliers
NOTE: This list is intended to be neither
comprehensive nor exclusive. Endorsement of any
particular product or company is not implied.
American Vegetable Grower
Meister Publishing Company
37733 Euclid Ave.
Willougby, OH 44094
(440) 942-2000
The annual “Source Book” issue (July) is a
comprehensive listing of manufacturers and
suppliers of every type of product for farmers,
including postharvest equipment and supplies. 12
issues/$15.95. Single issue/$2.75.
Cady Industries
P.O. Box 2087
Memphis, TN 38101
(800) 622-3695
Sells a 32” x 27” McKnit nylon bag with 1/8”
mesh for $6 each, with a minimum order of 10.
The Nylon Net Co.
845 North Main St.
Memphis, TN 38107
(800) 238-7529
Sells a ¼”nylon mesh “diver’s bag” with
drawstring, 24” x 34”, for $8.28 each.

12. ATTRA // POSTHARVEST HANDLING OF FRUITS & VEGETABLES Page 12121212
Delta Track
P.O. Box 398
Pleasanton, CA 94566
(800) 962-6776
Sells “Hygro Thermometers”: about the size of a
deck of cards, battery operated, digital display of
temperature and humidity, records daily min./max.
of each.
Spectrum Technologies
23839 W. Andrews Rd.
Plainfield, IL 60544
(800) 248-8873
Sells humidity monitors.
Barr, Inc.
1423 Planeview Dr.
Oshkosh, WI 54904
(920) 231-1711
e-mail: info@barrinc.com
http://www.barrinc.com
Distributor of used coolers, freezers, and
refrigeration systems.
Cool Care Consulting, Inc.
4020 Thor Dr.
Boynton Beach, FL 33426
(561) 364-5711
e-mail: ron.roberts@coolcareinc.com
http://www.coolcareinc.com
Sells postharvest pre-cooling and refrigeration
equipment, including forced air, ice, hydro,
vacuum, modular, and mobile cooling units.
Bio Safe Systems
80 Commerce St.
Glastonbury, CT 06033
(888) 273-3088
e-mail: Rob@biosafesystems.com
http://www.biosafesystems.com
Sells organic-approved, eco-friendly washwater
treatments/disinfectants.
By Janet Bachmann and Richard Earles
NCAT Agriculture Specialists
August 2000
The ATTRA Project is operated by the National Center for Appropriate Technology under a grant
from the Rural Business-Cooperative Service, U.S. Department of Agriculture. These
organizations do not recommend or endorse products, companies, or individuals. ATTRA is
located in the Ozark Mountains at the University of Arkansas in Fayetteville at P.O. Box 3657,
Fayetteville, AR 72702. ATTRA staff members prefer to receive requests for information about
sustainable agriculture via the toll-free number 800-346-9140.
The electronic version of Postharvest
Handling of Fruit & Vegetables is located
at:
http://www.attra.org/attra-
pub/postharvest.html

13. ATTRA // POSTHARVEST HANDLING OF FRUITS & VEGETABLES Page 13131313
APPENDIX I
Storage Conditions for Vegetables and FruitsStorage Conditions for Vegetables and FruitsStorage Conditions for Vegetables and FruitsStorage Conditions for Vegetables and Fruits
Temperature
F
% Relative
humidity
Precooling
method
Storage life
Days
Ethylene
sensitive
Apples 30-40 90-95 R, F, H 90-240 Y
Apricots 32 90-95 R, H 7-14 Y
Asparagus 32-35 95-100 H, I 14-21 Y
Avocados 40-55 85-90 14-28 Y
Bananas 56-58 90-95 7-28 Y
Beans, snap 40-45 95 R, F, H 10-14 Y
Beans, lima 37-41 95 7-10
Beets, roots 32 98-100 R 90-150
Blackberries 31-32 90-95 R, F 2-3
Blueberries 31-32 90-95 R, F 10-18
Broccoli 32 95-100 I, F, H 10-14 Y
Brussel sprouts 32 95-100 H, V, I 21-35 Y
Cabbage 32 98-100 R, F 90-180 Y
Cantaloupe 36-41 95 H, F 10-14 Y
Carrots, topped 32 98-100 I, R 28-180 Y
Cauliflower 32 90-98 H, V 20-30
Celery 32 98-100 I 14-28 Y
Cherries, sweet 30-31 90-95 H, F 14-21
Corn, sweet 32 95-98 H, I, V 4-6
Cranberries 36-40 90-95 60-120
Cucumbers 50-55 95 F, H 10-14 Y
Eggplant 46-54 90-95 R, F 10-14 Y
Endive 32 90-95 H, I 14-21 Y
Garlic 32-34 65-75 N 90-210
Grapefruit 50-60 85-90 28-42
Grapes 32 85 F 56-180
Kiwifruit 32 95-100 28-84 Y
Leeks 32 95-100 H, I 60-90 Y
Lemons 50-55 85-90 30-180
Lettuce 32 85-90 H, I 14-21 Y
Limes 48-50 85-90 21-35
Mushrooms 32 95 12-17
Nectarines 31-32 95 F, H 14-18 Y
Okra 45-50 90-95 7-14 Y
Onions, bulb 32 65-70 N 30-180
Onions, green 32 95-100 H, I 7-10
Oranges 32-48 85-90 21-56
Peaches 31-32 90-95 F, H 14-28 Y

14. ATTRA // POSTHARVEST HANDLING OF FRUITS & VEGETABLES Page 14141414
Temperature
F
% Relative
humidity
Precooling
method
Storage life
Days
Ethylene
sensitive
Pears 32 90-95 F, R, H 60-90 Y
Peas, in pods 32 95098 F, H, I 7-10 Y
Peppers, bell 45-55 90-95 R, F 12-18 Y
Peppers, hot 45-50 60-70 R, F 14-21 Y
Pineapple 45-55 85-90 14-36
Plums 32 90-95 F, H 14-28 Y
Potatoes, early 50-60 90 R, F 56-140
Potatoes, late 40-50 90 R, F 56-140 Y
Pumpkins 50-60 50-75 N 84-160
Radishes 32 95-100 I 21-28
Raspberries 32 90-95 R, F 2-3 Y
Rutabagas 32 98-100 R 120-180
Spinach 32 95-100 H, I 10-14 Y
Squash, summer 41-50 95 R, F 7-14 Y
Squash, winter 50-55 50-70 N 84-150
Strawberries 32 90-95 R, F 5-10
Sweet potatoes 55-60 85-90 N 120-210 Y
Tangerines 40 90-95 14-28
Tomatoes 62-68 90-95 R, F 7-28 Y
Turnips 32 95 R, H, V, I 120-150
Watermelon 50-60 90 N 14-21
F = forced-air cooling, H = hydrocooling, I = package icing, R = room cooling, V = vacuum
cooling, N = no precooling needed. Sources: USDA Agricultural Marketing Service, Kansas State
University Cooperative Extension Service

15. ATTRA // POSTHARVEST HANDLING OF FRUITS & VEGETABLES Page 15151515
The Portacooler
A portable precooler designed by USDA
researchers can be built with readily
available materials at a cost of around
$1,200. The most expensive component
is an airconditioner. If a used
airconditioner is available, the initial
investment will be decreased. The
Portacooler can be towed to the field and
used to reduce field heat of berries,
vegetables, and other high-value crops
immediately after picking.
The structure of the Portacooler is a basic
wood frame and plywood panel
construction (see diagram). The outside
dimensions of the cooler are 4 feet high by
4 feet wide by 8 feet long. The frame is
made of 2 by 3's spaced 2 feet on center,
excluding the doorway and the air
conditioner space. The frames are
sheathed with 1/2 inch plywood. The
precooler is insulated with 2-inch thick
plastic foam that fits firmly between the
frame studs.
After the frame and sheathing are
completed, the electrical components can
be installed (see diagram). The standard
junction box, power switches, daily cycle
timer, and industrial thermostat control
box should be mounted on the outside of
the front wall near the air conditioner. An
adjustable, industrial thermostat control
box should be mounted on the outside of
the front wall near the air conditioner. An
adjustable, industrial thermostat must be
connected to the air conditioner to replace
the existing thermostat. Mount strip
heaters using copper wire so that they
contact the cooling coils of the air
conditioner. Mount the blower on the front
inside wall, centered above the air
conditioner so that the blower
discharge is 12 inches below the inside
ceiling.
All electrical components should be properly
grounded, and wiring should comply with
national and local electrical codes. Consult a
licensed electrician for more information
about how to install any components of the
electrical system.
The Portacooler can be powered from
either an electrical wall outlet or a
gasoline-powered generator. The main
electrical connection from the power
source is split to the individual switches.
From the switches, the power travels to the
blower and to the air conditioner. The
strip heaters and the thermostat are wired
from the timer. The timer creates a defrost
cycle by alternating power from the
compressor to the strip heaters. (An
interval of compressor shutdown time
should be approximately 2.5 minutes
during every 10 minutes.)
Once the cooler is assembled, and the
electrical components hooked up, mount the
air flow bulkhead. Mount the bulkhead with
blower discharge hoe flush with the edge of
the blower discharge, allowing a 6-inch-high
return-air gap along the floor.
All wood surfaces should be coated with
polyurethane and an all-weather sealer to
prolong the useful equipment life.
APPENDIX II

16. ATTRA // POSTHARVEST HANDLING OF FRUITS & VEGETABLES Page 16161616
General Material List
• air conditioner, 12,000 Btu, 115 V......................................................................................................1
• centrifugal blower, 1/3 hp, 1210 c.f.m. ............................................................................................1
• 20-amp wall switch, with boxes and covers ...................................................................................2
• 4 by 8 ft, exterior AC, 1/4-in plywood.............................................................................................11
• lumber, 2 by 3 in, 8 ft long..................................................................................................................30
• lumber, 2 by 4 in, 12 ft long................................................................................................................3
• lumber, 2 by 6 in, 8 ft long..................................................................................................................1
• industrial wheels, 5-in diameter........................................................................................................2
• industrial wheels, 5-in diameter, swivel..........................................................................................2
• dry wall screws, 2 1/2-in long...........................................................................................................5 lb
• dry wall screws, 1-in long ..................................................................................................................1 lb
• water sealer...........................................................................................................................................1 gal
• polyurethane coating ..........................................................................................................................1 gal
• weather stripping, 1-in wide roll ......................................................................................................1
• insulation, 2 in, 4 by 8 ft sheets..........................................................................................................5
• 1/4-in plywood, 4-in wide strips......................................................................................................12 ft
• door latch, sliding bolt........................................................................................................................1
• thermostat, 115 B, 16 amp, remote bulb ..........................................................................................1
• strap hinges, screw fastened, 3-in long............................................................................................4
• lumber, 2 by 10 in, 4 ft long................................................................................................................1
• standard junction box .........................................................................................................................1
• strip heaters, 150 watt, 8 in, 115 B.....................................................................................................2
• insulated wire.......................................................................................................................................30 ft
• cycle timer, SPDT, 115 B, 20 amp, 1 hour ........................................................................................1
The design, construction, and research of the Portacooler was conducted by Joseph Anthony,
Gerald Berney, William Craig, and Daniel P. Schofer. For further information, contact Daniel
Schofer, Room 1211 South Bldg., 12 & Independence, Box 96456, Washington, D.C. 20090-6456.

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